1. Field of the Invention
The invention disclosed herein relates to apparatus for sorting articles in accordance with their weight, and more particularly, to such apparatus for performing such an operation accurately and quickly on a large number of such articles with separate weighing operations being performed upon each individual article.
2. Description of the Prior Art
A number of systems have been developed in the past which function to sort certain items in accordance with the item weights where such sorting is implemented by sensing the weights of the items and by thereafter directing the items to predetermined collection points as determined by their weights. Such a system is seen in U.S. Pat. No. 3,764,044 to Harben et al in which a pivoting scale beam is caused to move by the weight of passing poultry carcasses. The movement of the scale beam about its pivot is sensed by a photoelectric device which produces a signal when exposed to a beam of light from a light source. The scale beam has a plate attached thereto in which an aperture is formed. If the scale beam is deflected through a small angle by a light weight bird, the aperture never attains a position between the light source and the photosensor and no signal is provided therefrom. If the weight of a bird is greater than desired, the aperture in the plate passes between the light source and the photosensor quickly thereby exposing the photosensor to the light source for only a brief period of time. If this period is too brief the resistive-capacitive network coupled to the photosensor output is not charged and insufficient signal is generated to provide a sorting signal. If the weight of a bird is within the desired range, the aperture exposes the photosensor to the light source for a sufficient length of time for the resistive-capacitive network to charge to the point where it reaches a potential of sufficient level to cause a transistor to conduct and actuate a holding circuit coupled to an actuator which diverts the bird of desired weight size to a predetermined sorting point.
Another system relating to sorting by weight is disclosed in U.S. Pat. No. 3,627,127 to Whiteford, which includes a feed conveyor for delivering articles one at a time to a platform on a weighing unit. An output conveyor is provided for moving the weighed articles past a number of lateral channels. Transfer structure is provided for each channel so that the conveyed articles may be diverted from the output conveyor to specific channels according to weight. A strain gage weight sensor provides a voltage sample corresponding to the weight of each article being conveyed. The strain gage output is utilized to gate a clock to a counter which provides an output that is subsequently converted to a voltage and is indicative of weight. The counter output voltage and the strain gage voltage are compared, and, as long as they differ, clock pulses are continuously gated to the counter. The gate is closed when the comparator senses substantial equivalency between the strain gage output and the counter output. The counter value is then transferred to a register and subsequently transferred stepwise through successive registers associated with each channel until a match is made between the counter value and a reference number preset at each channel. The weighed item is discharged in the channel where the match is obtained.
U.S. Pat. NO. 3,640,384 to Del Rosso discloses a single weighing station together with a conveyor which carries a succession of buckets with bottoms that are opened by gravity when a section of underlying guide rail is temporarily removed. The buckets carry items which are weighed at the single weighing station, and the weights are recorded in a mechanical memory. The memory information is used to remove one of the underlying rail sections at a predetermined downstream discharge station so that the bottom of a bucket for which a predetermined weight was recorded is opened and the bucket contents are deposited at the discharge station.
U.S. Pat. No. 2,759,603 to Bradley discloses a system including an approach conveyor which feeds a weighing conveyor. A scale which is normally in a locked condition is released when an item to be weighed is properly positioned thereupon. The scale swings through one undamped scale oscillation after release. A plate having a number of apertures therein is attached to the part of the scale which swings through the undamped oscillation. The plate passes between a light source and a photo sensor. A number of light pulses are therefore received by the photosensor in accordance with the number of apertures on the plate that pass between the photosensor and the light source. A large scale arm oscillation passes a larger number of apertures between the light source and the sensor and thereby provides a greater number of output pulses from the photosensor. The number of pulses dictates the character of an actuation signal which is used to energize a predetermined downstream gate so that the weighed object is diverted to a predetermined path in accordance with its weight. No memory is utilized in the Bradley device since the weighing and diversion of the articles are both performed before any subsequent articles are weighed.